[jhc] A possible bug with constraints being perceived as multiparameter type classes

[Brandon Allbery]

On Tue, Apr 21, 2015 at 9:26 AM, Artyom <yom at artyom.me> wrote:

>  $ Temp/jhc-0.8.2/jhc Temp/jhc1.hs
>
> jhc Temp/jhc1.hs
> jhc 0.8.2 (mydniquipepo-32)
> Finding Dependencies...
> Using Ho Cache: '/home/yom/.jhc/cache'
>
> Temp/jhc1.hs:1   - Error: Invalid Class. multiparameter classes not yet supported:
> (Num,[HsTyTuple [HsTyVar {hsTypeName = a},HsTyVar {hsTypeName = b}]])
>
> Am I misunderstanding something, or is it a legitimate bug?
> ​
>

Looks multiparameter to me:

    instance ... => Num (T a b Int) where

with T ~ (,,). Which is what the second line of the error message is
telling you, more or less.

-- 
brandon s allbery kf8nh                               sine nomine associates
allbery.b at gmail.com                                  ballbery at sinenomine.net
unix, openafs, kerberos, infrastructure, xmonad        http://sinenomine.net
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